The present invention is directed to a new and improved lifting device, namely a compact, pantographic-type jack, in which an object supported thereon remains horizontal or level while being raised or lowered thereby.
Automotive assembly plants have recently been requiring jacks that are provided with certain features, so that the jacks may be stored within the rim of a spare wheel. This calls for a jack to have very small dimensions. In particular, the jack cannot exceed 110 mm in an initial position, while when fully raised, must have a height of no less than 385 mm.
In turn, such a jack must support a car in a lifted position and not slip when the lifting operation is performed on a smooth surface, e.g. on a glazed or neat-surface cement flooring.
Effort to rotate a jack handle must be low, no more than 8 kg, while the jack must be lightweight, no more than 2 to 3 kg, because the greater the deadweight of a vehicle, then the greater the fuel consumption when the latter is being driven.
Known pantographic-type jacks are generally good and secure, but fail to meet one or more of the above-noted requirements.